Tug captains use landmarks (points on land visible from the water) to tell other mariners and the Coast Guard VTS (Vessel Traffic Service - the harbor equivalent of air traffic controllers) where they are. This is not always as straightforward as it sounds, but it is proof that maritime history lives on.
A typical radio call is "headed westbound into Buttermilk turning off at Dikeman Street for Red Hook”
Dikeman Street has not been visible from the water since the late 1920s. It dead ends into the “Snapple building,” now owned by Est4te Four. The big 'Snapple' sign on the waterside of the building is roughly in line with Dikeman Street.
“The armory” on the VHF refers to the ATF building between the Snapple building and Valentino Park.
Sometimes the terms used have a very broad meaning: "bound for Red Hook" means that the vessel is going to anywhere Gowanus, Erie Basin or out to sea, anywhere the Bay Bridge Channel leads.
The meme below was created by a tugboat captain to tease new crew about not referring to places by landmarks long gone.